Through wall sub!!

indus

Distinguished Member
Wasn't sure quite how else to describe it!

At the moment I have the huge XTZ 3x12 lying on its side underneath my screen. I've covered it in speaker cloth and you can't really see it with the lights off but its beginning to annoy me.
In addition I'd like to lower my screen but can't at the moment because of the sub.

If you look at the pic below you'll see what I mean. It's an old pic but gets the point across





The room behind the screen is a utility room and the wall between the two is just a stud partition. So I wondering whether I could cut an opening in the wall and put the sub in the other room. The drivers all face forward.



The body of the sub would be in the utility room and it's face ie the drivers would be about flush with the remainder of the stud wall. I would then drop the screen so the sub drivers would be just behind the AT screen.

Can anybody see any acoustic problems associated with my hare brained scheme??

Thanks for looking
 

DodgeTheViper

Moderator
Is it a fixed frame screen ?
 

indus

Distinguished Member

indus

Distinguished Member
Actually please ignore. It was a stupid idea!
 

paulst10

Distinguished Member
Actually please ignore. It was a stupid idea!
I think it's a good idea but potentially a huge risk on your part, it's one of those things that you have to try it to find out..
 
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indus

Distinguished Member
I think it's a good idea but potentially a huge risk on your part, it's one of those things that you have to try it to find out..
True. I've decided to look into going at the problem a different way. I'll get rid of that sub and replace with two in wall subs to go behind the screen.

Thanks

Can't you build a false wall and bring the screen forward a few feet to hide the sub ?

I guess the only issue you may have is if air movement from the port may move the screen material slightly at heavy action parts !
The room isn't that large to start with, I really can't afford to lose a few feet. As mentioned, I'm going to look into into multiple in wall subs.

Cheers
 

MrNismo

Active Member
How about building your seating sofa "around" the sub!
Basically sitting atop the sub:p

I have memories of being at "The Fridge" in Brixton in the early 90s with people sitting on the massive speakers looking "well chuffed"
 

indus

Distinguished Member
It'd work fine, but could you not just put it somewhere else in the room ?
The sub is huge, it's got three 12 inch drivers and my room isn't that big so its almost impossible to find another location for it.

I'm going to hunt for in wall sub solutions.

Cheers
 

KelvinS1965

Distinguished Member
I'm going to hunt for in wall sub solutions.
Just a warning; it won't be cheap. ;) I'm a bit loath to mention them after your other thread ;), but I needed some in-wall subs to help fill in a null around 50-60Hz in my room. I looked at various options (including building more of my own, since my 'main' subs are DIY). I ended up with a pair of MK IW28S, but powered by my own iNuke amp rather than the (suitably expensive ;) ) matching MK amp.

I've run them on their own and they are very good for music and of course for filling in the null. However, they don't do much below 30Hz (in fact they do nothing at all in my set up as I've rolled them off to protect them as my main subs do the below 30Hz content anyway).

I'd have thought to get something equal to the XTZ 3x12 you would need something much bigger (and therefore even more expensive) than my pair of IW28S: I believe JL Audio do an in-wall sub, but I would imagine the price is probably eye watering. Even then it may not be as good as your current in room sub, so you may need to temper your expectations a little.

The other issue is that it's hard to have a demo of anything in-wall. I did at least try my subs placed in front of the wall (since they have a back on them), before installing them. Other makes may not work that way, so you'll only hear how good they are after they are installed...
 

indus

Distinguished Member
Just a warning; it won't be cheap. ;) I'm a bit loath to mention them after your other thread ;), but I needed some in-wall subs to help fill in a null around 50-60Hz in my room. I looked at various options (including building more of my own, since my 'main' subs are DIY). I ended up with a pair of MK IW28S, but powered by my own iNuke amp rather than the (suitably expensive ;) ) matching MK amp.

I've run them on their own and they are very good for music and of course for filling in the null. However, they don't do much below 30Hz (in fact they do nothing at all in my set up as I've rolled them off to protect them as my main subs do the below 30Hz content anyway).

I'd have thought to get something equal to the XTZ 3x12 you would need something much bigger (and therefore even more expensive) than my pair of IW28S: I believe JL Audio do an in-wall sub, but I would imagine the price is probably eye watering. Even then it may not be as good as your current in room sub, so you may need to temper your expectations a little.

The other issue is that it's hard to have a demo of anything in-wall. I did at least try my subs placed in front of the wall (since they have a back on them), before installing them. Other makes may not work that way, so you'll only hear how good they are after they are installed...

Hi Kelvin
Rest assured you can suggest anything you like, I won't bite your head off:D

You're absolutely right, these solutions are pretty damn expensive. And in terms of performance I might well have to accept lower performance. But to be honest in my 5.5m by 3m room the 3x12 is probably over kill anyway.

I've got loads of googling to do to explore all the options. I want to overhaul the cinema room and make it look tidier. In the end I'll be buying on gut feeling and crossed fingers because as you say auditioning these kind of custom install products is very difficult.

Best wishes
 

KelvinS1965

Distinguished Member
Cheers Indus.

I've just remembered one I did start to look into, that was a bit more palitible in cost terms. It is an in-wall made by BK Electronics (the Monolith people incase you weren't aware), called the iW300 (not to be confused with the MK Sound IW300):

iW300

You would need something like an iNuke or similar external power amp, but you would be able to run multiples of these (as was my original plan, to run 4 of them in each corner of my room). You might need to look into other options for amps if you wanted something that has a 12 volt trigger and iNuke amps are noisy too (mine are outside of the room in a rack under the stairs, so it doesn't bother me). Perhaps you would be able to put them in the room behind your screen though?
 

indus

Distinguished Member
Cheers Indus.

I've just remembered one I did start to look into, that was a bit more palitible in cost terms. It is an in-wall made by BK Electronics (the Monolith people incase you weren't aware), called the iW300 (not to be confused with the MK Sound IW300):

iW300

You would need something like an iNuke or similar external power amp, but you would be able to run multiples of these (as was my original plan, to run 4 of them in each corner of my room). You might need to look into other options for amps if you wanted something that has a 12 volt trigger and iNuke amps are noisy too (mine are outside of the room in a rack under the stairs, so it doesn't bother me). Perhaps you would be able to put them in the room behind your screen though?
Now thats much more reasonably priced. I could run four of those!

Ermmm.. can you make something (suitably sturdy) to have your current sub above the screen if the screen is lowered?
Wow. Now that's a curve ball! Very interesting indeed. The sub weighs 77kgs so it won't be easy.....

Thanks
 

BriD

Well-known Member
Wow. Now that's a curve ball! Very interesting indeed. The sub weighs 77kgs so it won't be easy.....
A single wall bracket on a rawlplug is going to struggle, but maybe brace it off the ceiling if you can find some joists.

Not sure if you want it decoupled from the structure of the house though, in which case some sort of free standing frame. If you think about even a thin IKEA bunkbed, they'll take a grown adult plus a mattress so 77kg should be easy.

I'm sure it could be done if you put your mind to it!
 

indus

Distinguished Member
A single wall bracket on a rawlplug is going to struggle, but maybe brace it off the ceiling if you can find some joists.

Not sure if you want it decoupled from the structure of the house though, in which case some sort of free standing frame. If you think about even a thin IKEA bunkbed, they'll take a grown adult plus a mattress so 77kg should be easy.

I'm sure it could be done if you put your mind to it!

The walls on the sides are solid cavity walls so they should be able to support some serious weight.
So perhaps a 'shelf' all the way across
 

indus

Distinguished Member
Thanks. I wonder what the acoustic repercussions will be of a sub firing along the ceiling above everybody's heads?:D:eek:
 

BriD

Well-known Member
Thanks. I wonder what the acoustic repercussions will be of a sub firing along the ceiling above everybody's heads?:D:eek:
I was wondering that whilst out for a run just now but then I had a lightbulb moment. The sound doesn't know which way up it is. So, pretend it's on the ceiling by leaving it on the floor and gluing your sofa to the ceiling.

Or.......

With sub on the floor and you sat down, your head is maybe 1m off the floor, and you have a 2.4m high ceiling I presume?

Well just stand up and crouch down to 1.4m so your head is 1m from the ceiling and 1.4m above the plane of the sub. Should be roughly the same. I doubt carpet etc will make much difference to bass.
 
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KelvinS1965

Distinguished Member
In the REW room sim you can position subs and speakers any height you like. In fact one of the (many) iterations I tried during the planing stages of my room involved having 4 of those iW300 BK subs at the back of the room at each 'corner'.

REW sim showed some good results from doing this and it helped smooth the bass wherever the MLP was moved to (subs at the front too). In this case it's just a single sub, so there may be a slight change of whatever null you normally have at the MLP due to a change of distance, but that could be compensated by moving the MLP slightly forward as well.
 

rhinoman

Well-known Member
I'm in exactly the same position, room upgrade/remodelling and sub upgrade. I really want to go with in wall subs for neatness too.
I've been playing with room sim as well and my 5.7m*3.5m room has the same issues as Kelvins with a large null at 50Hz, cured mainly by using a sub at the other end of the room with around a 8hz difference in response but even better with a bit more.
I'm leaning towards the Definitive Technology DT UIWSUBREF which is a 13" sealed unit with a pressure coupled bass radiator which they claim goes down to 14Hz. They also do a 10" model at a lower price point that goes to 16Hz.
A pair of those at the front and then a pair of something that only goes down to around 32Hz at my rear gives me a fantastically flat response across all four seating positions according to the room sim. I'm leaning towards one of the Kef in-wall models for the rear, probably a pair of the KEF Ci4100QLB will suit, my only reservation is the are open backed.
 

indus

Distinguished Member
I'm in exactly the same position, room upgrade/remodelling and sub upgrade. I really want to go with in wall subs for neatness too.
I've been playing with room sim as well and my 5.7m*3.5m room has the same issues as Kelvins with a large null at 50Hz, cured mainly by using a sub at the other end of the room with around a 8hz difference in response but even better with a bit more.
I'm leaning towards the Definitive Technology DT UIWSUBREF which is a 13" sealed unit with a pressure coupled bass radiator which they claim goes down to 14Hz. They also do a 10" model at a lower price point that goes to 16Hz.
A pair of those at the front and then a pair of something that only goes down to around 32Hz at my rear gives me a fantastically flat response across all four seating positions according to the room sim. I'm leaning towards one of the Kef in-wall models for the rear, probably a pair of the KEF Ci4100QLB will suit, my only reservation is the are open backed.

Hi
Thanks, I'll google the DT sub a bit later.

How will you run the four subs from your AVR? Does it have two outputs and you'll split each of them with a Y splitter of some kind?

Cheers
 

rhinoman

Well-known Member
Probably going to try splitting it first and then run the Dirac and see what it does.

The REW room sim looks so good with the right subs in the right position that its not going to need a lot of work. If it doesn't work brilliantly then the probable plan b is to add a minidsp hd and use MSO first to sort the subs out first before Dirac.
 

D1gita1

Active Member
  • Yes it will work fine
  • Dont put a sub at ceiling level
  • Keep the drivers back from the screen at least 3 or 4 inches.
  • Mount the screen slightly off the wall so there's no back pressure to vibrate the screen.
I think it's worth being able to drop the screen and get a cleaner look to the room.
 

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